螺杆泵井地面驱动系统的有限元模态分析

Finite element modal analysis of ground driving system for progressing cavity pump

针对螺杆泵井存在地面驱动系统振动问题,根据地面驱动系统的工作原理和结构特点,对螺杆泵井地面驱动系统结构进行了简化。利用有限元分析软件ANSYS7.0,选用四面体单元SOLID45,并采用映射网格与自由网格相结合的网格划分方法,建立了螺杆泵井地面驱动系统的三维有限元模型。采用子空间法,计算得到地面驱动系统的前8阶固有频率和主振型。将地面驱动系统的有限元模态分析结果与其工作频率进行对比分析,结果表明,某些工作频率与固有频率接近,从而引起系统较强烈的振动。通过振型图和动画显示,可直观地观察到螺杆泵地面驱动系统的动态特性和薄弱环节。研究成果为有针对性地改进地面驱动系统的结构提供了理论依据。

According to the operation principles and structural characteristics of the ground driving system of the progressing cavity pump, the structure of the ground driving system was simplified. A three-dimensional finite element model for the ground system was developed using the software ANSYS 7.0, tetrahedron element SOLID 45 and method of dividing the net lattice by mapped and free meshing. The natural frequencies and vibration types before the eighth step were obtained by the subspace method. The comparison of the result analyzed by finite element model with the working frequency shows that some working frequencies are close to the natural frequencies,which will result in strong vibration of the driving system. The animated shaking pictures can indicate the dynamic characteristics and weak points of the system. The analytic result can provide the theoretical basis for improving the structure of the ground driving system.